Ciso Tool
Ciso Tool
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Founded in 2006, Dongguan Ciso Tool Co., Ltd. has evolved into a global leader in the research, development, and high-volume manufacture of mid-to-high-end precision watch components and comprehensive OEM/ODM watch solutions. Formerly operating under an earlier corporate structure, our enterprise has consolidated design, structural engineering, and micro-precision machining into a unified, vertically integrated production ecosystem.
Headquartered in China's manufacturing heartland, we operate an independent, modern industrial facility encompassing over 20,000 square meters. Guided by an unwavering commitment to quality, our workforce comprises more than 500 highly trained personnel, including a dedicated, in-house R&D engineering division of over 60 specialists. This deep technical pool allows us to continuously push the limits of material science and mechanical tolerances, servicing international watch brands, boutique micro-brands, and optical instrument developers worldwide.
Our core competency lies in the manufacturing of high-performance watch crystal domes (synthetic sapphire and hardened mineral glass), custom watch dials, engineered cases, bracelets, buckles, and precious metal components. Whether executing single-dome, double-dome, or complex high-box vintage geometries, our manufacturing processes are tailored to satisfy strict military, diving, and haute horology standards.
We implement rigorous multi-stage quality assurance protocols at every phase of processing. From optical spectrophotometer checking to 100% mechanical dimension measurement, our products conform to international quality benchmarks, ensuring flawless clarity, high thermal shock resistance, and enduring structural integrity.
Empirical metrics defining our leadership in precision component manufacturing
Addressing the critical challenges faced by watch brands, OEM procurement directors, and micro-brands during technical specification and volume importing.
Single-domed crystals create a magnifying lens effect, distorting the dial at oblique angles. We specialize in engineering Double-Domed Crystals where the inner and outer curvature radii are perfectly aligned, eliminating visual refraction and offering crystal-clear legibility.
For professional dive watches, domestic glass components can fail under pressure. Our custom engineered sapphire domes undergo stress-relieving thermal cycles and precision edge chamfering, allowing them to withstand hydrostatic environments exceeding 100 ATM (1000m depth).
Low-quality AR coatings scratch easily, degrading the watch's premium appearance. We apply military-grade, multi-layer physical vapor deposition (PVD) coatings that pass rigorous eraser, humidity, and cross-hatch adhesion testing, achieving transmission rates up to 99.5%.
Choosing the right substrate and shape defines the watch's positioning, durability, and target retail price. Our factory processes three main material categories to cover all horological and industrial demands.
| Substrate Material | Hardness (Vickers / Mohs) | Refractive Index | Best Application Area | Key Manufacturing Advantage |
|---|---|---|---|---|
| Synthetic Sapphire (Single-Crystal Al₂O₃) | 2000 HV / 9 Mohs | 1.76 - 1.77 | Luxury Watches, Dive Instruments, Military Equipment | Unmatched scratch resistance, diamond-cutting precision, high thermal stability |
| Hardened Mineral Glass (SiO₂ Compound) | 700 HV / 6.5 Mohs | 1.52 | Mid-tier Fashion Watches, Everyday Sport Watches | Cost-effective, highly shatter-resistant compared to sapphire, accepts chemical tempering |
| Acrylic / Plexiglass (PMMA) | 20 HV / 3 Mohs | 1.49 | Heritage Vintage Reissues, Low-Cost Fashion Watches | Extremely lightweight, easy to buff out minor scratches, flexible high-dome profiles |
Single Dome: The crystal is curved on the outside and flat on the inside. This configuration is economical but causes visual distortion when viewed from the side. It is best suited for watches where the dial design is relatively flat and the watch thickness must be kept to a minimum.
Double Dome: The crystal is curved on both the outside and inside, with the inner radius calculated to complement the outer radius. This keeps the glass thickness uniform throughout, neutralizing the magnification factor and allowing the watch face to remain readable at extreme angles.
Without AR coatings, reflective glare can make reading the dial difficult. We utilize advanced high-vacuum electron-beam evaporative deposition to deposit ultra-thin layers of metal oxides (such as TiO₂ and SiO₂). Brands can specify:
The interface between the watch crystal and the bezel is a critical seal point. Our CNC grinding machines finish the edges of the crystals with high precision, maintaining tolerances within ±0.01mm. We offer polished chamfers, stepped profiles, and frosted edge designs tailored to match your case and gasket configuration.
How we manufacture high-precision watch crystal domes from raw materials to final QC delivery
Synthetic sapphire boules or mineral glass blocks are sliced into thin blanks using diamond wire saws.
Multi-axis CNC grinding machines shape the initial dome contours, defining the R1 (outer) and R2 (inner) curvatures.
Mineral glass crystals undergo ion-exchange tempering to increase structural impact strength and crack resistance.
Continuous optical polishing lines using diamond paste achieve a surface roughness (Ra) of under 0.2nm, ensuring absolute clarity.
Crystals are cleaned in ultrasonic lines, then loaded into high-vacuum chambers for multi-layer dielectric AR deposition.
Every crystal batch undergoes strict inspection via laser interferometers, spectrophotometers, and dimensional tolerances checks.
Inside our Dongguan Ciso manufacturing facility, featuring advanced precision machinery, testing rooms, and assembly operations
We guarantee transparent supply chains and standard compliance. Each production lot comes with material purity certificates, dimension check reports, and AR transmittance curve readouts.
Sourcing precision components internationally requires navigating technical and legal compliance. At Dongguan Ciso Tool Co., Ltd., we align our manufacturing standards with the demands of top-tier global watch brands and industrial clients.
Chemical and Ecological Compliance: Our watch crystals, mineral glass compounds, customized gaskets, and metallic coatings undergo testing by third-party laboratories (SGS, TUV) to guarantee compliance with RoHS Directive 2011/65/EU and REACH EC Regulation 1907/2006. This simplifies customs clearance and ensures environmental compliance for our clients in Europe and North America.
Optical Grade Packaging: To prevent micro-abrasions, surface contamination, and chipping during global transit, crystals are packed using clean-room standards. Every crystal is placed in custom-molded thermoformed trays (anti-static ESD trays) and vacuum-sealed, preventing any movement or atmospheric exposure during maritime or air shipment.
Expert technical answers regarding watch crystal dome selection, customization options, and factory processes
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